The wings of the modern aircraft are equipped with the leading edge flaps, which are advanced during takeoff and landing for increasing the lift. The compound differential planetary gearing is used in the leading edge flaps mechanics when it is necessary to provide high-torque low-speed power transmission connecting the flap surface to the spar. It was realized that the fatigue cracks may occur in the certain areas of the ring gear in between the teeth propagating towards the OD surface. In order to prevent the accident such cracks should be detected at the earliest possible stage.
The while-on-wing rapid detection of the small cracks of the ring gear is now possible with use of the PA modality based technology from Sonotron NDT.
The inspection is illustrated by the video below: whilst scanning with the small PA probe circumferentially over the OD surface of the ring gear the direct reflection echoes received from the teeth appear one-by-one on the True-To-Geometry sectorial scan image. The tip-diffraction echoes from the cracks are easy distinguishable appearing is the separately designated region of interest.
The inspection may be implemented with the use of Sonotron NDT’s ISONIC 3510, ISONIC 2010, ISONIC 2009 portable ultrasonic flaw detectors.